Remote Ischemic Pre- and Postconditioning Improve Postresuscitation Myocardial and Cerebral Function in a Rat Model of Cardiac Arrest and Resuscitation

Objectives: Cardiac arrest and resuscitation are models of whole body ischemia reperfusion injury. Postresuscitation myocardial and cerebral dysfunction are major causes of high mortality and morbidity. Remote ischemic postconditioning has been proven to provide potent protection of the heart and brain against ischemia reperfusion injury. In this study, we investigated the effects of remote ischemic postconditioning on postresuscitation myocardial and cerebral function in a rat model of cardiac arrest and resuscitation.

Design: Prospective, randomized, controlled experimental study.

Setting: University-affiliated animal research institution.

Subjects: Twenty-eight healthy male Sprague-Dawley rats.

Interventions: The animals were randomized into four groups: 1) remote ischemic preconditioning initiated 40 minutes before induction of ventricular fibrillation, 2) remote ischemic postconditioning initiated coincident with the start of cardiopulmonary resuscitation, 3) remote ischemic postconditioning initiated 5 minutes after successful resuscitation, and 4) control. Remote ischemic pre- and postconditioning was induced by four cycles of 5 minutes of limb ischemia, followed by 5 minutes of reperfusion. Ventricular fibrillation was induced and untreated for 6 minutes while defibrillation was attempted after 8 minutes of cardiopulmonary resuscitation. The animals were then monitored for 4 hours and observed for an additional 68 hours after resuscitation.

Measurements And Main Results: Hemodynamic measurements and myocardial function, including cardiac output, left ventricular ejection fraction, and myocardial performance index, were measured at baseline and hourly for 4 hours after resuscitation. Postresuscitation cerebral function was evaluated by neurologic deficit score at 24-hour intervals for a total of 72 hours. Consequently, significantly better myocardial and cerebral function with a longer duration of survival were observed in the three groups treated with remote ischemic pre- and postconditioning.

Conclusions: In a rat model of cardiac arrest and resuscitation, remote ischemic pre-and postconditioning attenuated postresuscitation myocardial and cerebral dysfunction and improved the duration of survival.